Study to Evaluate Safety and Immunogenicity of a Pandemic Flu H5 mRNA Vaccine in Healthy Adults Aged 18 Years and Older

A Phase 1/2, Randomized, Modified Double-blind, Placebo-controlled, Multi-center, Dose Escalating Study to Evaluate the Safety and Immunogenicity of a Pandemic Flu H5 mRNA Vaccine in Healthy Adults Aged 18 Years and Older

The purpose of this study is to evaluate a pandemic flu H5 strain messenger ribonucleic acid (mRNA) vaccine at 3 dose levels (low, medium, and high) in comparison with placebo in 276 healthy adult participants to select the adequate dose for further clinical development.

The duration per participant will be approximately 13 months.

Study Overview

• Status: Completed
• Conditions: Influenza Immunization
• Intervention / Treatment: Biological: Pandemic flu H5 mRNA vaccine; Other: Placebo

• Study Type: Interventional
• Enrollment (Actual): 276
• Phase: Phase 2; Phase 1

Contacts and Locations

Study Locations

• United States
  • California
    • La Mesa, California, United States, 91942
      • Velocity Clinical Research - San Diego- Site Number : 8400013
  • Florida
    • DeLand, Florida, United States, 32720
      • Accel Research Sites Network - DeLand Clinical Research Unit- Site Number : 8400002
    • Lakeland, Florida, United States, 33803
      • ARSN-Lakeland CRU- Site Number : 8400006
    • Largo, Florida, United States, 33777
      • Accel Research Sites - St. Petersburg- Site Number : 8400004
  • Georgia
    • Atlanta, Georgia, United States, 30342
      • Atlanta Clinical Research Center- Site Number : 8400007
    • Decatur, Georgia, United States, 30030-2627
      • Accel Research Site - NeuroStudies.net, LLC - ERN - PPDS- Site Number : 8400003
  • Michigan
    • Bingham Farms, Michigan, United States, 48334
      • QUEST Research Institute- Site Number : 8400014
  • Nebraska
    • Norfolk, Nebraska, United States, 68701
      • Velocity Clinical Research - Norfolk- Site Number : 8400015
    • Omaha, Nebraska, United States, 68134
      • Velocity Clinical Research - Omaha- Site Number : 8400012
  • Ohio
    • Cincinnati, Ohio, United States, 45246
      • Velocity Clinical Research - Springdale- Site Number : 8400010
  • South Carolina
    • North Charleston, South Carolina, United States, 29405
      • Coastal Carolina Research Center - North Charleston- Site Number : 8400001
  • Texas
    • Sugar Land, Texas, United States, 77479
      • Olympus Clinical Research - Sugar Land- Site Number : 8400009
  • Utah
    • West Jordan, Utah, United States, 84088
      • Velocity Clinical Research, Salt Lake City- Site Number : 8400011
  • Virginia
    • Charlottesville, Virginia, United States, 22911
      • Charlottesville Medical Research- Site Number : 8400005

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Aged 18 years or older on the day of inclusion.

• A female participant is eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies:

  • Is of non-childbearing potential. To be considered of non-childbearing potential, a female must be postmenopausal for at least 1 year, or surgically sterile.

OR

• Is of childbearing potential and agrees to use an effective contraceptive method or abstinence from at least 4 weeks prior to each study intervention administration until at least 12 weeks after the last study intervention administration.

• A female participant of childbearing potential must have a negative highly sensitive pregnancy test (urine or serum as required by local regulation) within 8 hours before the first dose of study intervention.

Exclusion Criteria:

• Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months).
• Known systemic hypersensitivity to any of the study intervention components (eg, polyethylene glycol, polysorbate); history of a life-threatening reaction to the study interventions used in the study or to a product containing any of the same substances; any allergic reaction (eg, anaphylaxis) after administration of an mRNA vaccine .
• Previous history of myocarditis, pericarditis, and/or myopericarditis.
• Known history of previous episodes of Guillain-Barré Syndrome (GBS), neuritis (including Bell's palsy), convulsions , encephalitis, transverse myelitis, and vasculitis.
• Participants with an electrocardiogram that is consistent with possible myocarditis or pericarditis or, in the opinion of the investigator, demonstrates clinically relevant abnormalities that may affect participant safety or study results.
• Self-reported thrombocytopenia, contraindicating IM injection based on investigator's judgment.
• Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating IM injection based on investigator's judgment.
• Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion.
• Moderate or severe acute illness / infection (according to investigator's judgment) or febrile illness (temperature ≥ 38.0°C [≥ 100.4°F]) on the day of study intervention. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
• Alcohol, prescription drug, or substance abuse that, in the opinion of the investigator, might interfere with the study conduct or completion.
• Participant who had acute infectious symptoms or a positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse transcriptase polymerase chain reaction (RT PCR) or antigen test in the past 10 days prior to the first visit (V)01.
• Receipt of any vaccine other than an mRNA vaccine in the 4 weeks preceding study intervention administration or planned receipt of any vaccine other than an mRNA vaccine in the 3 weeks following the second dose of the study intervention .
• Receipt of immune globulins, blood or blood-derived products in the past 3 months.
• Receipt of any mRNA vaccine/product in the 2 months preceding study intervention administration or planned receipt of any mRNA vaccine in the 2 months after the second dose of the study intervention.
• Participation at the time of study enrollment (or in the 4 weeks preceding study intervention administration) or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure.
• Previous history of participation in an H5 influenza A vaccine study. This includes any influenza subtypes that contain H5 such as H5N1, H5N8, or H5N6.

Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Sequential Assignment
• Masking: Triple

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group 1: Low Dose Pandemic flu H5 mRNA vaccine; Participants will receive 2 injections of pandemic flu H5 mRNA vaccine 21 days apart (at Day 01 and Day 22)	Biological: Pandemic flu H5 mRNA vaccine; Pharmaceutical Form: Suspension for injection Route of Administration: Intramuscular (IM)
Experimental: Group 2: Medium Dose Pandemic flu H5 mRNA vaccine; Participants will receive 2 injections of pandemic flu H5 mRNA vaccine 21 days apart (at Day 01 and Day 22)	Biological: Pandemic flu H5 mRNA vaccine; Pharmaceutical Form: Suspension for injection Route of Administration: Intramuscular (IM)
Experimental: Group 3: High Dose Pandemic flu H5 mRNA vaccine; Participants will receive 2 injections of pandemic flu H5 mRNA vaccine 21 days apart (at Day 01 and Day 22)	Biological: Pandemic flu H5 mRNA vaccine; Pharmaceutical Form: Suspension for injection Route of Administration: Intramuscular (IM)
Placebo Comparator: Group 4: Placebo; Participants will receive 2 injections of placebo 21 days apart (at Day 01 and Day 22)	Other: Placebo; Pharmaceutical Form: Liquid solution for injection Route of Administration: Intramuscular (IM)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Presence of immediate adverse events (AEs) within 30 minutes after each/any injection	Number of participants experiencing immediate AEs	Within 30 minutes of any/each injections
Presence of solicited injection site reactions through 7 days after each/any injection	Number of participants experiencing solicited injection site reactions	Through 7 days after each/any injections
Presence of solicited systemic site reactions through 7 days after each/any injection	Number of participants experiencing solicited systemic site reactions	Through 7 days after each/any injections
Presence of unsolicited AEs through 21 days after the first injection and through 28 days after the second injection	Number of participants experiencing unsolicited AEs	Through 21 days after the first injection and through 28 days after the second injection
Presence of medically attended adverse events (MAAEs) through 180 days after the last injection	Number of participants experiencing MAAEs	Through 180 days after the last injection
Presence of adverse events of special interest (AESIs) throughout the study	Number of participants experiencing AESIs	Throughout the study, approximately 13 months
Presence of serious adverse events (SAEs) throughout the study	Number of participants experiencing SAEs	Throughout the study, approximately 13 months
Presence of out-of-range biological test results (including shift from baseline values) through a maximum of 8 days after each injection	Number of participants with out-of-range biological test results	Through a maximum of 8 days after each injection

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Antibody titers measured by Hemagglutination Inhibition (HAI) Assay	Antibody titers are expressed as geometric mean titers (GMTs)	At Day 01, Day 22, Day 43, Day 112, and Day 202
Individual HAI titer ratio		At Day 22/Day 01, Day 43/Day 01, Day 112/Day 01, and Day 202/Day 01
≥ 4-fold increase in HAI titer [1/dilution])		At Day 22 or Day 43
HAI titer ≥ 10 [1/dilution]		At day 01
HAI titer ≥ 40 [1/dilution]		At Day 01, Day 22, Day 43, Day 112, and Day 202
Detectable HAI titer ≥ 10 [1/dilution]		At Day 01, Day 22, Day 43, Day 112, and Day 202
Antibody titers measured by Seroneutralization (SN) test	Antibody titers are expressed as GMTs	At Day 01, Day 22, Day 43, Day 112, and Day 202
Individual SN titer ratio		Day 22/Day 01, Day 43/Day 01, Day 112/Day 01, and Day 202/Day 01
SN titer ≥ 20 (1/dilution)		At Day 01, Day 22, Day 43, Day 112, and Day 202
SN titer ≥ 40 (1/dilution)		At Day 01, Day 22, Day 43, Day 112, and Day 202
SN titer ≥ 80 (1/dilution)		At Day 01, Day 22, Day 43, Day 112, and Day 202
Detectable SN titer ≥ 10 (1/dilution)		At Day 01, Day 22, Day 43, Day 112, and Day 202
2-fold rise in SN titer		At Day 22 and Day 43
4-fold rise in SN titer		At Day 22 and Day 43

Collaborators and Investigators

• Sponsor: Sanofi Pasteur, a Sanofi Company

Publications and helpful links

Helpful Links

• VBS00001 Plain Language Results Summary

Study record dates

Study Major Dates

• Study Start (Actual): December 9, 2024
• Primary Completion (Actual): March 24, 2026
• Study Completion (Actual): March 24, 2026

Study Registration Dates

• First Submitted: December 5, 2024
• First Submitted That Met QC Criteria: December 5, 2024
• First Posted (Actual): December 10, 2024

Study Record Updates

• Last Update Posted (Actual): April 23, 2026
• Last Update Submitted That Met QC Criteria: April 22, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: pandemic influenza infection; H5 strain
• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; Orthomyxoviridae Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Influenza, Human
• Other Study ID Numbers: VBS00001; U1111-1309-8833 (Other Identifier: WHO ICTRP)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No